Anode material for lithium ion secondary battery, anode for lithium ion secondary battery, and lithium ion secondary battery
An anode material for a lithium ion secondary battery that includes a carbon material having an average interlayer spacing d 002 as determined by X-ray diffraction of from 0.335 nm to 0.340 nm, a volume average particle diameter (50% D) of from 1 μm to 40 μm, a maximum particle diameter D max of 74 μm or less, and at least two exothermic peaks within a temperature range of from 300° C. to 1000° C. in a differential thermal analysis in an air stream.
1. An anode material for a lithium ion secondary battery, comprising a carbon material having an average interlayer spacing d 002 as determined by X-ray diffraction of from 0.335 nm to 0.338 nm, a volume average particle diameter (50% D) of from 1 μm to 40 μm, a maximum particle diameter D max of 74 μm or less, and at least two exothermic peaks that comprise an exothermic peak having a peak within a temperature range of from 300° C. to less than 700° C. and an exothermic peak having a peak within a temperature range of from 700° C. to 745° C.
2. The anode material for a lithium ion secondary battery according to claim 1 , wherein the at least two exothermic peaks comprise an exothermic peak having a peak within a temperature range of from 500° C. to less than 700° C.
3. The anode material for a lithium ion secondary battery according to claim 1 , wherein a difference in peak temperatures between an exothermic peak having a peak at a highest temperature from among the at least two exothermic peaks, and an exothermic peak having a peak at a lowest temperature from among the at least two exothermic peaks is 200° C. or less.
4. The anode material for a lithium ion secondary battery according to claim 1 , wherein a specific surface area of the carbon material at 77 K as determined by nitrogen adsorption measurement is from 0.5 m 2 /g to 25 m 2 /g.
5. The anode material for a lithium ion secondary battery according to claim 1 , wherein an R value obtained from a Raman spectroscopic analysis of the carbon material is from 0.10 to 1.5.
6. The anode material for a lithium ion secondary battery according to claim 1 , wherein the carbon material comprises a first carbon phase that serves as a core, and a second carbon phase that is present on a surface of the first carbon phase and has a lower crystallinity than the first carbon phase.
7. The anode material for a lithium ion secondary battery according to claim 6 , wherein a content ratio of the second carbon phase is from 0.1° A by mass to 30% by mass with respect to a total mass of the carbon material.
8. An anode for a lithium ion secondary battery, comprising: an anode material layer that includes the anode material for a lithium ion secondary battery of claim 1 ; and a current collector.
9. A lithium ion secondary battery comprising the anode for a lithium ion secondary battery of claim 8 , a cathode and an electrolyte.
10. The anode material for a lithium ion secondary batter according to claim 1 , wherein a tapped density of the carbon material is from 0.5 g/cm 3 to 2.0 g/cm 3 .
11. The anode material for a lithium ion secondary batter according to claim 1 , wherein a tapped density of the carbon material is from 0.5 g/cm 3 to 1.3 g/cm 3 .
12. The anode material for a lithium ion secondary batter according to claim 1 , wherein a tapped density of the carbon material is from 0.3 g/cm 3 to 2.0 g/cm 3 .
13. The anode material for a lithium ion secondary batter according to claim 1 , wherein an adsorption amount of the carbon material at 273 K as determined by carbon dioxide adsorption measurement is from 0.1 cm 3 /g to 5.0 cm 3 /g.
14. An anode material for a lithium ion secondary battery comprising:
a carbon material comprising:
a first carbon phase that serves as a core;
a second carbon phase that is present on a surface of the first carbon phase and has a lower crystallinity than the first carbon phase, wherein a content of the second carbon phase is from 0.1° A by mass to 30% by mass with respect to a total mass of the carbon material;
an average interlayer spacing d 002 as determined by X-ray diffraction from 0.335 nm to 0.338 nm;
a volume average particle diameter (50% D) from 1 μm to 40 μm;
a maximum particle diameter D max of 74 μm or less;
at least two exothermic peaks that comprise an exothermic peak having a peak within a temperature range of from 300° C. to less than 700° C. and an exothermic peak having a peak within a temperature range of from 700° C. to 745° C.; and
a surface functional group including oxygen within the second carbon phase, wherein an amount of the oxygen relates to the content of the second carbon phase, and the amount of oxygen in terms of an elemental composition of the carbon material is 0.5 to 5 atom %.
15. The anode material for a lithium ion secondary batter according to claim 14 , wherein the surface functional group including oxygen is selected from the group consisting of C—O, C═O, C—OH and C—OOH.
16. The anode material for a lithium ion secondary batter according to claim 14 , wherein a tapped density of the carbon material is from 0.5 g/cm 3 to 2.0 g/cm 3 .
17. The anode material for a lithium ion secondary batter according to claim 14 , wherein a tapped density of the carbon material is from 0.5 g/cm 3 to 1.3 g/cm 3 .
18. The anode material for a lithium ion secondary batter according to claim 14 , wherein a tapped density of the carbon material is from 0.3 g/cm 3 to 2.0 g/cm 3 .
19. The anode material for a lithium ion secondary batter according to claim 14 , wherein an adsorption amount of the carbon material at 273 K as determined by carbon dioxide adsorption measurement is from 0.1 cm 3 /g to 5.0 cm 3 /g.